Hi Stuart,
If you believe that the code is wrong - change it. Raise a tracker, submit the changes along with a test plan, get it peer reviewed.....and make a difference. Nothing was ever achieved by moaning about it.
There is no 'why'. Moodle is old and decisions made in the past on how things were done are based upon the knowledge known at the time. Things have moved on. And when old code is recognised to be out of date then it needs to be improved for the very reasons the new knowledge justifies.
Gareth